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RSD PUZZLE #21
Symptoms used to diagnose RSD
"I have suffered from RSD for the past eight years. In the first few years,
sympathetic nerve blocks helped me. Last month the doctor did a diagnostic sympathetic
nerve block which did not relieve my pain. The doctor says that I do not have RSD because
the diagnostic test ruled it out. How can I not have RSD when I have had all the other
findings of it in the past eight years?"
One of the most accurate ways of diagnosing RSD in a patient who has had other
manifestations of it (constant burning pain, weakness or movement disorder of the
extremity, emotional disturbance, and insomnia, as well as evidence of swelling and
inflammation of the extremity) is to do a sympathetic ganglion or IV Phentolamine) tests.
In the first two to three years, such a sympathetic nerve block test definitively relieves
the patient from her pain. Such a positive response of pain relief proves that the patient
suffers from "SYMPATHETICALLY MEDIATED PAIN" (SMP).
However, after two to three years of suffering from RSD, the longstanding poor circulation
and constriction of the blood vessels as well as the inflammation and swelling secondary
to RSD, affect the non-sympathetic (somatic) nerves as well. So the patient develops not
only SMP but also the pain that is independent of sympathetic system function due to the
lack of oxygen to the somatic nerve fibers (non-sympathetic nerve fibers). This type of
pain, which does not respond to sympathetic nerve blocks, is called "SYMPATHETICALLY
INDEPENDENT PAIN" (SIP).
The end result is that longstanding RSD causes the development of a pain that is
independent of the sympathetic system due to the poor circulation and the swelling. The
patient develops pain that is severe, has the sympathetic component of a constant burning
pain, but sympathetic block loses its effect due to the long- standing damage to the
nerves.
Because of lack of familiarity with such a complex phenomenon, a lot of patient are
accused of having never had RSD and they are deprived of treatment due to the SIP
component of the pain.
As long as in the early stages of the disease the patient has had SMP (sympathetically
maintained pain) confirmed by complete relief of pain to sympathetic nerve blocks, there
is no reason to doubt the illness later on when the condition becomes more complicated.
Another factor is that even though Phentolamine IV nerve block relieves the sympathetic
pain, attempts at sympathetic nerve block by direct injection to the sympathetic nerve
ganglia (such as stellate ganglion block) even in the best of hands and in the hands of
the most experienced physicians faces a one-fourth (approximately 25%) risk of the block
not being successful due to anatomical variation and due to the fact that the sympathetic
ganglion is not exactly where it is supposed to be. So, because of this one-fourth failure
rate of technically and successfully blocking the sympathetic ganglion, the RSD cannot be
ruled out on the basis of "SIP" diagnosis.
There is no one test in the world that can definitively 100% rule in or rule out RSD. Even
IV Phentolamine test is fraught with handicaps of not completely relieving the pain of RSD
due to the simultaneous complication of SIP if the patient's original injury has also
caused some somatic (non-sympathetic) nerve damage to the area involved with RSD.
As the world literature reflects, the fact that the triphasic bone scan test is successful
in only 55 to 65% of the patients[1]. This is due to the fact that RSD not infrequently
causes symmetrical bilateral involvement in the extremities also due to the fact that in
chronic RSD that has been partially treated the bone scan may be insensitive and may not
show the abnormal isotope uptake in the extremities. Thermography is not, by far, 100%
positive in RSD patients, and at best has a sensitivity of around 80%. Both bone scan and
thermography, like any other test (including MRI and CAT scan), are handicapped by
false-positive and false-negative results and showing changes expected in RSD patients
when the patient already has had an old injury and does not suffer the full picture of RSD
anymore.
The diagnosis of RSD should always be a clinical diagnosis. The diagnosis of RSD cannot be
made on the basis of "ruling out other causes". It is an insensitive and
inaccurate way of diagnosing RSD.
There is no way one can "rule out" other causes. The patient with cancer, RSD,
epilepsy, or any other serious illness can also suffer from the clinical manifestations
(conversion reaction) and/or malingering. Just to prove conversion reaction or malingering
does not rule out co-existence of cancer, RSD, multiple sclerosis, or other complex and
serious illnesses.
The best guideline for the diagnosis of RSD is the presence of the following
criteria:
1. A constant burning pain that is elicited even with a breeze or a touch (allodynia).
2. Any manifestation of the disturbance of motor function in the extremity such as
constriction of the blood vessels (cold extremity and poor circulation), or movement
disorder such as tremor, dystonia and flexion spasm, atrophy or weakness of the muscles of
the extremity.
3. Evidence of inflammation (swelling) in the involved area. This may be in the form of
simple swelling (edema), skin rash (neuro-dermatitis), spontaneous bleeding, blotchy skin,
and other forms of discoloration of the skin.
4. Disturbance of limbic system function. The sensory sympathetic nerve fibers ascend
through the spinal cord up to the brainstem and thalamus and terminate in limbic system
(marginal system which is at the margin of old and new brain). This system, which is
mainly over the temporal lobe and frontal lobe regions, is responsible for control of
emotion, expression of proper judgment, and memory function, and control of diurnal cycle
(through the brainstem influence on the sleep wakeful cycle).
A true RSD patient suffers from insomnia, agitation, depression, disturbance of judgment
manifested by willing to have any type of operation and any other type of treatment that
comes by, and complications of attempted suicide, as well as weight fluctuation.
Without some manifestation of the above four categories, one cannot make the diagnosis of
RSD. RSD cannot be ruled in or out by trust of exclusion. For example, if the patient has
carpal tunnel syndrome secondary to RSD, then the patient's diagnosis is not a simple
carpal tunnel syndrome but RSD causing carpal tunnel syndrome, etc.
H. Hooshmand, M.D.
Reference:
1. Lee GW, Weeks PM: The role of bone scintigraphy in diagnosing reflex sympathetic
dystrophy. J Hand Surg [Am]. 1995; 20:458-463.
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